Heretofore, it has been well known to provide hatch covers for railcars. More particularly, the heretofore known vented hatch covers included passageways with openings to the outside air and to the compartment which is closed by the cover for the purposes of allowing the venting of air between the outside and the compartment and which allow unloading of the contents without removing the cover. Where shippers of goods want to assure no contaminants can be transferred by air flow, a non-vented hatch cover is used.
When unloading a compartment of a railcar having non-vented hatch covers, it is necessary to remove the hatch covers in order to provide sufficient air flow into the compartment to allow the contents to be discharged from the compartment and also to eliminate any implosion risks during unloading operations.
Accordingly, there is a need to provide a hatch cover for a hatch opening that will seal out contaminants during shipping while also allowing unloading without the necessity of removing the hatch cover from the opening.